In an existing prior art related to a color measurement instrument as disclosed in the U.S. Pat. No. 7,262,853 B2, an illumination system is disposed perpendicularly to an internal side of a casing, and a sensor is installed slantingly on another side of the casing. The illumination system comprises an illuminator, a tube, an upper end connected to the illuminator, a lower end having a convex lens, and the central line of the convex lens aligned with a sample. The sensor comprises a flat lens having its central line aligned with the sample, an aspherical lens installed at the top of the flat lens, and an optoelectronic diode installed at an upper end of the aspherical lens.
The drawback of the aforementioned structure resides on that the illuminator of the illumination system projects light radially onto the sample directly through the tube and the convex lens, and thus the light projected at the center of the projected area is stronger, and the light projected at the periphery of the projected area is weaker, and the uniformity of the light projected onto the projected area is affected adversely. Furthermore, the whole illumination system is installed linearly with the sample, such that after the illumination system is turned on, a strong light reflected from the center of the sample will be received, and the temperature at the area of the illumination system will rise rapidly. As a result, the components in the system will be damaged easily. The illuminating light, the convex lens and the sample are aligned linearly, such that after a light is projected onto the sample, the light is diffused progressively outward and then reflected, and such phenomenon causes the sensor to receive a majority of reflected light directly from the aforementioned reflected light, so that after an optoelectronic diode receives an image signal, there are substantial drawbacks on the shape of a light spot and the color distortion of an image.
In view of the foregoing drawbacks of the prior art, the inventor of the present invention based on years of experience in the related industry to conduct extensive researches and experiments, and finally developed a color measurement instrument in accordance with the present invention to overcome the drawbacks.